Battery with improved electrolyte and electrodes

Abstract

The description relates to a battery device, comprising: - electrodes comprising an anode and a cathode, and - an electrolyte, between the electrodes, comprising a crystalline material of composition M2B2O5.x(HOH).y(NOH), where M and N are alkali or hydrogen elements or mixtures of alkali or hydrogen elements, B is titanium, O and H denote respectively the elements oxygen and hydrogen, and x and y are between 0 and 4 and denote a presence of H+, OH-, N+ ions, capable of migrating in the crystalline material. In particular, at least one type of ion among H+, OH-, N+ and M+ is mobile to migrate in the crystalline material towards at least one of the electrodes, and said at least one of the electrodes is made of a material capable of operating a chemical interaction with at least one of the H+, OH-, M+ and N+ ions. Abstract Figure: Figure 5

Description

Title of the invention: Battery with improved electrolyte and electrodes Technical field

[0001] The present disclosure relates to the field of batteries, both in the form of a cell or fuel cell and a rechargeable battery. Prior art

[0002] Document WO-2018 / 060656 presented a particularly promising material for forming the electrolyte of a supercapacitor, this material being solid crystalline and of structure A2B2O5 with A possibly being an alkali and B possibly being titanium. The performance of this material led the inventors designated in this document to envisage an application as a battery, which is mentioned in the aforementioned document (in particular page 12, lines 15-30, with reference to [Fig.8] of the document).

[0003] Nevertheless, the embodiment presented aims to consider the whole of the electrolyte attached to the two electrodes as a “pseudo-battery” in the sense that the electric discharge (“rapid, of the order of a few minutes, then relatively slow thereafter, of the order of a few hours”) could not be perfectly controlled and jackets of piezoelectric elements PZ1, PZ2, PZ3, etc. remained necessary to mechanically constrain or relax the material in order to block or release the electric charges.

[0004] Typically, the materials intended for the electrodes were carbon, or a metal such as copper, silver, gold or platinum, simply to ensure collection of electrons. Summary

[0005] The present disclosure improves the situation.

[0006] It proposes to keep a similar material for the electrolyte but to improve the materials chosen for the electrodes in order to better manage the charging / discharging of the device and to increase the energy density that can be stored, by involving a controlled chemical interaction between the material of an electrode and ions capable of moving in the material of the electrolyte.

[0007] Thus, a battery device is targeted, comprising: - electrodes comprising an anode and a cathode, and - an electrolyte, between the electrodes, comprising a crystalline material of composition M2B2O5.x(HOH).y(NOH), where M and N are alkali elements or hydrogen, or mixtures of alkali elements or hydrogen, B is titanium, O and H denote respectively the elements oxygen and hydrogen, and x and y are between 0 and 4 and denote a presence of H+, OH, N+ ions, capable of migrating into the crystalline material, device in which at least one of the ions among H+, OH, N+ and M+ is mobile to migrate in the crystalline material towards at least one of the electrodes, and said at least one of the electrodes is made of a material capable of carrying out a chemical interaction with at least one of said ions H+, OH, N+ and M+.

[0008] The term “chemical interaction” is understood above to mean an intercalation of the ion migrating towards the electrode or a chemical reaction between this ion and the material of the electrode. Thus, the aforementioned chemical interaction comprises one of the following elements: - an intercalation of said at least one of the H+, OH, N+ and M+ ions in said at least one of the electrodes, and - a chemical reaction (typically electrochemical) of said at least one of the ions H+, OH, N+ and M+ with the material of said at least one of the electrodes.

[0009] In the device of the aforementioned document WO-2018 / 060656, the migrating ionic species accumulated in the vicinity of the electrodes and thus generated an accumulation of charge allowing the collection, storage and restitution of electrical energy, but in a purely electrostatic form. Thus, the quantity of energy stored in the device produced according to the teaching of document WO-2018 / 060656 remained limited by the electrostatic nature of the storage.

[0010] Here, the chemical interaction with the electrode makes it possible to control the charge / discharge more efficiently, and to increase the storage energy density.

[0011] It is not provided in the prior art cited above that the electrodes can be composed of materials specifically intercalating ions or giving rise to electrochemical reactions with the migrating ionic species. Thus, it was not taken into account that the migrating species in the electrolyte (namely in particular OH, H+, O2) could react chemically with the materials which compose the electrodes or else intercalate therein.

[0012] Thanks to the present implementation, the battery device within the meaning of the present description is provided with the microscopic faradic mechanisms usually present in battery, cell or fuel cell type embodiments and making it possible to finely control the charging or discharging of such a device. More precisely, the energy density is improved here by adding intercalation mechanisms, ion absorption or electrochemical reactions to the surface of the electrodes used as well as by broadening the choice of migrating species in the electrolyte. The choice of materials constituting the electrodes was then made in accordance with the migrating species or species in the electrolyte in order to be able to produce a rechargeable battery type device or a cell or a fuel cell.

[0013] The solid electrolyte can be in the form of single crystals, ceramics, pressed powders, membranes or thin layers. It has the general formula M2Ti2O5 .x(H2O) or M2Ti2O5.x(NOH) with M being one or more alkalis (and / or the element hydrogen); N being one or more alkalis (and / or the element hydrogen) and x being able to be equal to 0. This electrolyte material is noted “MTO” hereinafter, for the sake of brevity.

[0014] The electrode materials may be in solid, liquid or gaseous form, as discussed below.

[0015] In a typical embodiment, the battery device may comprise an anode made of a material comprising a metal hydride, for a chemical reaction with migrating ions of the OH type.

[0016] Alternatively, the anode can be made of a material comprising at least one element from Zinc, Iron and Aluminum (or sodium or lithium), for a chemical reaction with migrating ions of the OH type.

[0017] Alternatively, the anode can be made of a material comprising dihydrogen, for a chemical reaction with migrating ions of the OH type.

[0018] As for the cathode, it can contain a mixture of oxygen and water.

[0019] For example, the cathode may be made of a material comprising nickel oxohydroxide (NiOOH).

[0020] Alternatively, the cathode may comprise silver oxide (AgO).

[0021] In such an embodiment, the cathode may be initially made of a material comprising silver (Ag), and silver oxide (AgO) may then form at an interface with the electrolyte, typically when the cathode is left in ambient air (in particular to provide said mixture of oxygen and water, mentioned above), in accordance with the embodiment described later with reference to [Fig. 6].

[0022] In a particular embodiment, the device can exploit the migrating H+ and OH ions in the electrolyte, and comprise: - a cathode made of a material containing silver and intercalating the OH ions, and - an anode made of a material having a structure of type M2B3O7 where M is an alkali element or mixtures of alkali elements, B titanium, and O the oxygen element, to intercalate the H+ ions.

[0023] Alternatively, the device may comprise: - a cathode made of a material containing silver and intercalating the OH ions, and - an anode made of a material containing graphite and intercalating the H+ ions.

[0024] Alternatively, in a battery device where x=0 and M and / or N comprise at least one element from sodium and lithium, the device may comprise: - an anode made of a material comprising one element from sodium and lithium respectively (for example in metallic form), and - a cathode allowing the incorporation of sodium and / or lithium ions.

[0025] For example, such a cathode can be made of a material from graphite and a structure of type M'2B3O7 where M' is an alkali element or mixtures of alkali elements, B titanium, and O the oxygen element, to intercalate the migrating ions M+ and / or N+.

[0026] In one or more embodiments presented above, the anode material and the electrolyte material can be deposited successively in the form of respective thin layers (this embodiment being typically easy to implement when the anode is made of a material of M2B3O7 structure).

[0027] In one or more embodiments presented above, at least the anode is encapsulated in a resin-type material or equivalent to be airtight and moisture-tight.

[0028] Additionally, the entire device (anode, electrolyte and cathode) may be encapsulated in a resin-type material or equivalent to be airtight and moisture-proof.

[0029] When the electrode materials are in solid form or when one of the electrodes is simply made of ambient air (for example the cathode in certain embodiments presented above), it is then possible to produce a so-called “all-solid” battery.

[0030] More generally, the choice of materials at the anode and cathode can be made as follows: the value of the standard redox potential of the couple involved at the anode (EOa) must be lower than the value of the standard redox potential of the couple involved at the cathode (EOc). Depending on the choice of electrodes, it is then possible to classify the achievements by the nature of the migrating species within the electrolyte.

[0031] In an embodiment exploiting the migration of OH ions, the electrolyte material will create high mobility OH hydroxide ions, by spontaneous hydration.

[0032] In this case, to manufacture for example a rechargeable battery, it may be advantageous to choose: - a metal hydride (such as MgH2 for example) as anode material, and - Nickel oxohydroxide (NiOOH) as cathode material.

[0033] To make another type of battery: - a metal such as Zinc (or Iron or even Aluminum, or a mixture) can be provided at the anode, and - silver oxide (AgO), or an O2 - H2O mixture, can be provided as cathode material.

[0034] To make a fuel cell: - dihydrogen may be provided as anode material, and - a mixture of O2 - H2O can be provided as cathode material.

[0035] Furthermore, the generation of a mixed migration of both hydroxide ions OH- and hydrogen ions H+ is possible and can be advantageously exploited.

[0036] Indeed, by including oxygen vacancies in the structure of the electrolyte material, it is possible to cause the dissociation of water vapor into H+ and OH. These two species can then migrate independently of each other, so that it is possible to have the following electrode choices.

[0037] A silver cathode, for example (Ag), can react electrochemically with OH ions, typically. At the anode, the intercalation or the electrochemical reaction of the H+ ions can be ensured by graphite-based compounds, or by a solid material close to that of the electrolyte, such as A2Ti3O7 with A being able to be an element among sodium Na, potassium K, or rubidium Rb, or any type of material capable of intercalating H+.

[0038] This embodiment has the advantage of growing on a suitable substrate a first electrode (anode) of the K2Ti3O7 type for example, having the property of intercalating the protons, then the solid electrolyte next, for example K2Ti2O5, easy to grow on the anode given the proximities of the crystalline phases (and mesh agreement for example), and finally a layer of Ag or graphite which does not pose any problem of deposition or interface on the solid electrolyte, to form the cathode.

[0039] This achievement makes it possible to solve the problem very often encountered in the field of all-solid-state batteries, which is the quality of the electrode / electrolyte interface when the two materials have crystallographic structures that are too different.

[0040] The migration of other species present in the electrolyte, such as Na+, can be exploited.

[0041] By adding sodium to the chemical formula of MTO, we obtain, for example, the material A2B2O5(NaOH) or A2 xNaxB2O5 which have high mobility Na+ ions in their structure.

[0042] Thus, for a rechargeable battery: - the anode material may include metallic sodium, and - the cathode material may comprise a graphite-based compound, or A2Ti3O7 with A being [Na, K, Rb] or other types of materials that can intercalate Na+

[0043] Depending on the migrating ionic species, other embodiments are possible of course. For example, for the exploitation of the migration of lithium ions Li+, it is possible, by adding lithium to the chemical formula of the electrolyte material, to obtain the material A2B2 O5(LiOH) or A2 xLixB2O5 each having high mobility Li+ ions in its structure.

[0044] For a rechargeable battery, it is possible to provide in the same way: - as anode material, metallic lithium, and - as cathode material, a graphite-based compound, or A2Ti3O7 with A being [Na, K, Rb] or other types of materials that can intercalate Li+. Brief description of the drawings

[0045] Other characteristics, details and advantages will appear on reading the detailed description below, and on analyzing the attached drawings, in which: Fig.l

[0046] [Fig.l] shows the crystallographic structure of an MTO electrolyte material according to one embodiment. Fig. 2

[0047] [Fig.2] shows the incorporation of a water molecule into such a material. Fig. 3

[0048] [Fig.3] shows the gain in thermodynamic energy as a function of a percentage of hydration of the sites of the structure of the material, which shows that the more numerous the water molecules are, the more stable they are. Fig. 4

[0049] [Fig.4] shows a comparison between the electrode arrangements in a mode “parallel” of the material (left figure) or in a “transverse” mode (right figure). Fig. 5

[0050] [Fig.5] shows a battery-type device, the electrolyte of which is based on the aforementioned MTO material, according to one embodiment. Fig. 6

[0051] [Fig.6] shows an embodiment of such a device whose electrodes are based on zinc and silver (oxidizing at the interface with the electrolyte). Fig. 7

[0052] [Fig.7] shows a device of the prior art within the meaning of document WO-2018 / 060656, comprising identical electrodes, gold in the exemplary embodiment. Fig. 8

[0053] [Fig.8] shows a comparison of the electrical performances of the devices of Figures 6 and 7. Description of the embodiments

[0054] The use of materials of the M2Ti2O5 family (or “MTO” hereinafter) with M = [Li, Na, K, Rb, H...] or a combination of these elements (of structure similar to that described in WO-2018 / 060656, and particularly Rb2Ti2O5 and K2Ti2O5 as solid electrolyte for all-solid energy storage devices. More generally, the family of compounds of formula M2TixO2x+i with x greater than or equal to 2 and M = [Li, Na, K, Rb] is considered here to offer such properties.

[0055] On a microscopic level, the MTO material is characterized by a lamellar structure with ionic bonds between the Ti2O52 and Rb22+ planes. The material is lamellar and cleavable along the planes located between the Rb atoms.

[0056] The non-hydrated or weakly hydrated material is capable of conducting ionic species such as H+, K+, Rb+, Na+, Li+ depending on the chemical formula of the compound which can combine several cations in its composition such as for example (Na,K)2Ti2O5.

[0057] Added to this are the possibilities offered by the hydrated MTO material, which is in fact a very hygroscopic material, especially in its powder form, and has the property of spontaneously adsorbing water vapor. Ab initio simulations using the density functional method have shown that this molecular water is preferentially organized into channels along the crystallographic direction corresponding to the b axis. Water is incorporated into the structure by creating hydrogen bonds with the apical oxygens of the perovskite structure according to Figures 1 and 2, corresponding to the most probable configuration according to simulations.

[0058] The addition of a water molecule in this configuration thus represents an energy variation at T=0 of -0.5 EV (PBEsol method) or -0.25 (HSE method).

[0059] [Fig.l] illustrates insertions of a water molecule creating very strong hydrogen bonds, inside the molecular structure of the material comprising Rb atoms (one atom being illustrated at the top right of [Fig.l]), O oxygen atoms (one atom being illustrated in the center of [Fig.l]), H hydrogen atoms (two atoms of which are represented to the right of the central oxygen atom of [Fig.l]), and Ti titanium atoms (bottom right of [Fig.l]). This structure, of general formula MTO is more particularly designated here “RTO”, the M atom of the general formula MTO, being an Rb atom. [Fig.l] thus illustrates the incorporation of a water molecule into the RTO (or more generally MTO) structure, creating two very short hydrogen bonds with the apical oxygen atoms of the structure.Furthermore, the simulations show that the energy gained by the addition of a water molecule to the structure increases with the number of water molecules in the same chain, as illustrated in Figures 2 and 3 commented on later, which favors the creation of chains of water molecules which can give rise in particular to a Grotthus-type proton conduction mechanism in water.

[0060] More generally, the migrating entities within the intercalated water can be one of of the following species: OH and / or M+ with M = [H, Li, Na, K, Rb] and / or O2.

[0061] The hydrophilic character of MTO promotes water absorption.

[0062] As illustrated in [Fig.2] for the MTO material with M=Rb, the water molecules arrange themselves in the MO planes (01 designating the apical oxygens of the structure). The molecules organize themselves in chains in the ab planes (forming channels), preferentially oriented with the ab planes parallel to the deposition substrate (so-called "parallel" orientation), or with the ac planes parallel to the substrate plane (so-called "transverse" orientation), as illustrated respectively on the left and right of [Fig.4], on which the lines represent the ab planes of the lamellar compound.

[0063] Typically, [Fig.3] shows the thermodynamic energy gain at temperature T=0 as a function of the percentage of hydration of the sites of the structure.

[0064] The MTO materials mentioned above can then be used as a solid electrolyte (therefore ionic conductor) for example in micrometric or nanometric, planar and crystalline shaping where the electrolyte consists of a thin layer of MTO deposited on a substrate S such as an integrated circuit by deposition technology such as PVD (Physical Vapor Deposition) or CVD (Chemical Vapor Deposition), including for example cathode sputtering, pulsed laser ablation, atomic layer deposition, molecular beam epitaxy, reactive plasma deposition, or others. The MTO layer is preferably monocrystalline and / or microcrystalline by regions.

[0065] The electrolyte can alternatively consist of thin layers of MTO obtained by exfoliation of sheets from a millimetric crystal. This sheet of nanometric thickness (up to a few hundred nm) can then be transferred to an integrated circuit where it naturally adopts a parallel orientation.

[0066] With reference to [Fig. 5], in these two cases, electrodes A and B are deposited (with vacuum deposition techniques) either on each side of the thin layer of MTO in the case of parallel orientation, or above and below the layer in the case of transverse orientation, so that ionic conduction takes place preferentially in the crystallographic plane ab (double arrow in [Fig. 5]).

[0067] A controlled hydration step of the thin layer can be implemented before or after the electrode depositions and before the possible encapsulation step. Finally, an encapsulant E (for example silicone, epoxy resin, or tropicalization, a polyurethane compound, or others) can be deposited on the whole in order to “freeze” a chosen hydration rate of the device.

[0068] Alternatively, the electrolyte may consist of MTO in massive (or "bulk") and crystalline form and may thus be composed of one or more oriented (stacking perpendicular to the ab crystallographic planes) and aggregated single crystals. together in a polymer matrix (epoxy resin, silicone or polyurethane compound). A controlled hydration step of the crystals can be implemented before encapsulation in the matrix.

[0069] Two electrodes A and B are deposited on each side of the encapsulated single crystals, so that ionic conduction takes place in the crystallographic plane ab, as illustrated by the double arrow in [Fig.5].

[0070] Alternatively, the creation of a massive device can use MTO cast in an encapsulant, the MTO material then having a crystalline form in membranes, ceramics or others. For example, the electrolyte can be composed of MTO crystals mixed with at least one organic or aqueous solvent (for example methyl-2-pyrrolidinone, water, ethanol, or others). A fluorinated compound dispersed in the solvent can also be added (for example polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), or others) in order to increase the mechanical stability of the construction. The size of the MTO crystals can vary from several mm to a few hundred nm. The volume percentage of MTO can be between 60% and 98% depending on the chosen solvent. A controlled hydration step can be considered before mixing the powder with the solvent used.Depending on the solvent chosen for the production of the device, the duration of the mixing process can extend over several tens of hours and include annealing steps of up to 150°C. Depending on the purpose of the production, the mixture can then be deposited on a non-adhesive substrate (such as a Teflon film) or on an electron collecting electrode, which can typically interact with ions (for example Zinc, Gold, Silicon, Sodium, and / or Lithium, metallic, or even silver oxide AgO, or others), as detailed below.

[0071] For this purpose, deposition methods may be, for example, inkjet injection, “Spin-Coater” deposition, or “Dr. Blade” deposition. A drying step may then take several dozen hours at a temperature of up to 150°C. After evaporation of the solvent, a film with a thickness ranging from a few micrometers to several millimeters is obtained. Subsequently, if the film has been deposited on one electrode, then the other electrode can be deposited on top of the film. If the film has been deposited on a non-adhesive substrate, then two electrodes are deposited on each side of the film. Then, it is possible to encapsulate the film with its electrodes, the encapsulant providing good mechanical strength, as well as air and moisture tightness.

[0072] In one embodiment, the electrolyte herein is composed of an MTO ceramic compacted at 10 tons for 2 hours at 150°C and sintered at 800°C for 10 hours. Alternatively, a mass fraction of 2 to 5% of PTFE (polytetrafluoroethylene) may be added to the MTO powder in order to make the ceramic stronger without going through the sintering step. The electrodes are then deposited with a Polymer-Solvent-Material mixture (PVDF 8%: Polyvinylidene - Solvent 84%: l-methyl-2-pyrrolidinone - Material 8%) and then dried for several hours at a temperature between 25 and 80°C. It is also possible to place the powders making up electrodes A and B in the press system in order to produce the electrodes at the same time as the ceramic.

[0073] The choice of possible electrodes, for the different shaping geometries of the energy storage devices described above, must be made according to the species migrating in the electrolyte and the type of device chosen. In the assemblies envisaged, the MTO material is used as a solid electrolyte placed between an anode consisting of a material having a standard redox couple E0a, and a cathode consisting of a material having a standard redox couple E0c, with E0a <E0c.

[0074] Different examples for producing the anode and the cathode are presented below. An asymmetry can be created between the cathode and the anode by encapsulating one of the electrodes and leaving the other electrode "in the air", which creates the possibility of supplying oxygen or water vapor to the device from only one side and which leads to super-capacitance effects.

[0075] The conduction of OH ions can be exploited in a battery type assembly (non-rechargeable battery) of the “Metal-Air” type. The materials which can be used as an anode are for example metallic zinc (Zn), metallic iron (Fe), metallic aluminum (Al), or a metallic alloy composed of at least two of the materials mentioned above.

[0076] An example of a redox reaction occurring at the anode is then:

[0077] Zn + 2 OH ZnO + H2O + 2 e

[0078] Materials that can be used as cathodes are, for example: - silver oxide: AgO, or - a N2 / O2 / H2O gas mixture: ambient air can typically be used (with a humidity level greater than 5% and less than 95%, an oxygen O2 level greater than 15% and less than 25%, a nitrogen N2 level greater than 75% and less than 85%), so that examples of redox reactions occurring at the cathode can be:

[0079] O2 + 2 H2O + 4 e 4 OH

[0080] AgO + H2O + 2 e Ag + 2 OH

[0081] Other embodiments may implement a NiMH (Nickel and metal hydride) accumulator type assembly. The materials that can be used as anode are for example: - AB_5 type alloys, for example based on rare earth (La, Ce, Nd, Pr), such as LaNi5 and derivatives, or alloys comprising elements from Ni, Co, Mn, Al, Mg, Zr, C, Co, Fe, Ti.

[0082] An example of a redox reaction occurring at the anode can then be:

[0083] OH + MH H2O + M + e , where M is a metallic element originally present in the form of metal hydride MH (such as TiH2 or MgH2).

[0084] Materials that can be used as cathodes are, for example: - Nickel oxohydroxide (NiOOH), or - a mixture of metal oxide (Ni-Co-Mg), or - a Ni-Co-Al alloy.

[0085] An example of a redox reaction occurring at the cathode may be:

[0086] NiO(OH) + H2O + e Ni(OH)2 + OH

[0087] For the exploitation of proton conduction, the materials which can be used as anode (negative electrode) can be for example: - WO3, MoO3, TiO2, H2Ti3O7, H2Ti60i3, H2Tii2O25 and other derivatives by substitution.

[0088] Materials that can be used as cathode (positive electrode) can be for example: - a metal oxide: RuO2, MnO2, V2O5, PbO2 - a protonated metal oxide: HCoO2 - materials with a structure analogous to Prussian Blue (“Prussian Bleu Analog materials” or “PBA”) for example AxM[Fe(CN)6]y.zH2O - or organic materials, for example PEDOT or HATN.

[0089] For the exploitation of the conduction of Li+ ions, the materials which can be used as anodes (negative electrode) are for example: - graphite carbon derivatives: carbon nanotubes, graphene, mesoporous carbon, etc. - metallic lithium (Li).

[0090] The materials that can be used to form the cathode (positive electrode) can be for example: - lithiated metal oxides, for example LiCoO2 - lithium intercalation compounds (e.g. a mixture of metal oxide (Ni-Co-Mg), a Ni-Co-Al alloy, Prussian Blue PBA structural materials, etc.).

[0091] For the exploitation of the conduction of Na+ ions, the materials which can be used to form the anode (negative electrode) are for example: - carbon derivatives (graphite, carbon nanotubes, graphene, mesoporous carbon, etc.), - metallic sodium (Na), - sodium alloys: Sodium-Tin (Na-Sn), Sodium-Lead (Na-Pb), Sodium- Bismuth (Na-Bi), - alloys of sodium and intercalated transition metals: Na-Mn-O, Na-Cr-S, Na-Ti-S, - tin-based compounds: SnO2, SnSb, - titanium lamellar oxides of the form Na2Ti3O7, Na^ijOn, NaTi2(PO4)3 from the family of the electrolyte material and depositable in a solid thin layer, - sodium or vanadium oxides: NaV2O5

[0092] Materials that can be used at the cathode (positive electrode) are for example - structural materials such as Prussian blue PBA, - TiSe2 - Na, Fe or Ni phosphate: NaFePO4, NaNiPO4 - Sodium oxide, manganese: NaMnO2 - Sodium, nickel, manganese oxide: Na(NiMn)O2 - Sodium oxide, Cobalt or Chromium: NaCoO2, NaCrO2 - Sodium oxide, nickel, Cobalt: Na(NiCo)O2 - Sodium oxide, copper: NaCuO2. Comparative examples

[0093] [Fig.6] illustrates an example of an embodiment of a device within the meaning of the present description, including: - the electrolyte comprises the MTO material obtained by implementing the above process from a single crystal or polycrystals compacted in a solvent then dried, between two electrodes, - the anode is made of a material containing zinc Zn, and encapsulated in a resin E to prevent oxidation, and - the cathode is made of a material containing silver Ag initially, but without being encapsulated, so that the silver oxidizes spontaneously in the open air and in contact with the MTO, so that the cathode material is in reality silver oxide AgO, and the rest of the initial material Ag serves to efficiently conduct the charges to the cathode wire Fc (made for example of silver, like the anode wire Fa).

[0094] A device in the sense of the prior art ([Fig.7]) was produced under strictly the same conditions, including: - the electrolyte comprises the MTO material obtained under the same conditions (from a single crystal or polycrystals compacted in a solvent then dried, between two electrodes), - the anode and the cathode are made of the same material containing gold (an excellent conductor but blocking ions), the anode being encapsulated in a resin E to be in the same experimental conditions as in the device of [Fig.6], the anode and cathode wires being made of silver, as previously.

[0095] Thus, this embodiment in the sense of [Fig.6] exploits a migration of OH ions reacting chemically with the Zn anode according to an equation of the type:

[0096] Zn + 2 OH ZnO + H2O + 2 e

[0097] At the AgO cathode, the ambient air naturally containing water vapor H2O and oxygen O2, the chemical equations are of the type:

[0098] O2 + 2 H2O + 4 e 4 OH

[0099] AgO + H2O + 2 e Ag + 2 OH

[0100] [Fig.8] illustrates a comparison of the results and cyclovoltametric curves of the devices of Figures 6 and 7.

[0101] The device of [Fig.6] shows a significant improvement over the prior art device ([Fig.7]). In [Fig.8], redox peaks (dotted curve) show the presence of electrochemical reactions that control the charging and discharging of the device. The capacitance is improved by a factor of 10 and the energy density by a factor of 20. In addition, the reversibility observed in the electrical discharge / charging of the device makes it a prime candidate for the manufacture of rechargeable batteries.

[0102] The performance of a device within the meaning of the present description can be even higher with very thin layers of electrodes and electrolyte which can be stacked, allowing further densification and improvement of the performance of the device per unit area.

Claims

Claims

1. Battery device, comprising: - electrodes comprising an anode and a cathode, and - an electrolyte, between the electrodes, comprising a crystalline material of composition M2B2O5.x(HOH).y(NOH), where M and N are alkali or hydrogen elements or mixtures of alkali or hydrogen elements, B is titanium, 0 and H denote respectively the elements oxygen and hydrogen, and x and y are between 0 and 4 and denote a presence of H+, OH, N+ ions, capable of migrating in the crystalline material, device in which at least one of the ions among H+, OH, N+ and M+ is mobile to migrate in the crystalline material towards at least one of the electrodes, and said at least one of the electrodes is made of a material capable of operating a chemical interaction with at least one of said H+, OH, N+ and M+ ions.

2. Device according to claim 1, comprising an anode made of a material comprising a metal hydride, for a chemical reaction with migrating ions of OH type.

3. Device according to claim 1, comprising an anode made of a material comprising at least one element among Zinc, Iron and Aluminum, for a chemical reaction with migrating ions of OH type.

4. Device according to claim 1, comprising an anode made of a material comprising dihydrogen, for a chemical reaction with migrating ions of OH type.

5. Device according to one of the preceding claims, in which the cathode comprises a mixture of oxygen and water.

6. Device according to one of the preceding claims, in which the cathode is made of a material comprising nickel oxohydroxide (NiOOH).

7. Device according to one of claims 1 to 5, in which the cathode comprises silver oxide (AgO).

8. A device according to claim 7, wherein the cathode is made of a material comprising silver (Ag), and wherein silver oxide (AgO) forms at an interface with the electrolyte.

9. Device according to one of claims 5 to 8, in which the cathode is left in the ambient air.

10. Device according to claim 1, in which the migrating ions in the electrolyte are H+ and OH, the device comprising: - a cathode made of a material comprising silver and intercalating the OH ions, and - an anode made of a material comprising a structure of type M2B3O7 where M is an alkali element or mixtures of alkali elements, B titanium, and 0 the oxygen element, to intercalate the H+ ions.

11. Device according to claim 1, in which the migrating ions in the electrolyte are H+ and OH, the device comprising: - a cathode made of a material comprising silver and intercalating the OH ions, and - an anode made of a material comprising graphite and intercalating the H+ ions.

12. Device according to claim 1, in which x=0 and M and / or N comprise at least one element from sodium and lithium, the device comprising: - an anode made of a material comprising one element from respectively sodium and lithium, and - a cathode allowing the incorporation of sodium and / or lithium ions.

13. Device according to claim 12, in which the cathode is made of a material among graphite and a structure of type M'2B3O7 where M' is an alkali element or mixtures of alkali elements, B titanium, and 0 the oxygen element, to intercalate the migrating ions M+ and / or N+.

14. Device according to one of the preceding claims, in which the anode material and the electrolyte material are deposited successively in the form of respective thin layers.

15. Device according to one of the preceding claims, in which the at least one anode is encapsulated in a resin-type material to be airtight and moisture-proof.

16. A device according to any preceding claim, wherein the entire device is encapsulated in a resin-like material to be airtight and moisture-proof.

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